Communication system

ABSTRACT

An embodiment of the invention relates to a communication node ( 10, 11 ) for a communication system ( 5 ). The embodiment is characterized by: a communication module ( 30 ), and at least one application module ( 21, 22 ), wherein the communication module is configured to transfer data signals (D 2 ) received from another communication node of the communication system, or the contents of these data signals, to the application module, and to send data signals (D 1 ) based on data received from the application module to said other communication node or to at least one other communication node of the communication system, wherein the communication module is configured to evaluate the received data signals and to generate a quality value (Q 1 (T 1 ), Q 2 (T 2 )) that describes the current and/or future quality of the data connection with respect to a previously defined maximum latency (T 1 , T 2 ) that is assigned to the application module, and wherein the communication module is further configured to send a control signal (QS) to the application module if the quality value is below a given quality threshold (Q 1 min, Q 2 min) regarding the respective maximum latency that is assigned to the application module.

The invention relates to communication systems, communication nodes andmethods of operating communication systems.

BACKGROUND OF THE INVENTION

German Patent Application DE 10 2012 206 529 A1 discloses a method ofoperating a token-ring system where communication nodes send signals toallocated upstream communication nodes and receive signals fromallocated downstream communication nodes.

OBJECTIVE OF THE PRESENT INVENTION

An objective of the present invention is to provide a method whichallows operating a communication systems in a very reliable way.

A further objective of the present invention is to provide acommunication system and a communication node that can be operated in avery reliable way.

BRIEF SUMMARY OF THE INVENTION

An embodiment of the invention relates to a communication node for acommunication system. The communication node is characterized by acommunication module and at least one application module. Thecommunication module is configured to transfer data signals receivedfrom one or more other communication nodes of the communication system,or the contents of these data signals, to the application module, and tosend data signals based on data received from the application module toat least one other communication node of the communication system. Thecommunication module is further configured to evaluate the received datasignals and to generate a quality value that describes the currentand/or future quality of the data connection with respect to apreviously defined maximum latency that is assigned to the applicationmodule. Moreover, the communication module is configured to send acontrol signal to the application module if the quality value is below agiven quality threshold regarding the respective maximum latency that isassigned to the application module.

An advantage of this embodiment of the invention is that thecommunication module may determine quality values based on maximumlatencies. The maximum latencies preferably define maximum time delaysor transmission durations (and as such required arrival times) for thetransmission and reception (at the remote communication nodes) of data,e.g. each data packet. As such, the communication module is capable ofgenerating control signals that can warn the application module(s) ifthe quality of the data connection is insufficient to meet therequested/required time constraints.

According to a preferred embodiment, the communication node comprises atleast two application modules. Preferably, an individual(module-individual) quality threshold and an individual(module-individual) maximum latency is assigned to each applicationmodule. The communication module is preferably configured to send acontrol signal to each of the application modules for which the assignedquality threshold exceeds the quality value for the respective maximumlatency. As such, each application module can take individual measuresif and when their (time/delay-related) quality demands are not met.

The communication system is preferably a token-ring system and thecommunication nodes are preferably broadcast-type communication nodes.

According to a further preferred embodiment, the data signals areencoded data packets. The communication module is preferably configuredto decode the received data packets and to determine the quality valuebased on, or at least also based on, the error rate of said received anddecoded data packets.

Further, the communication module is preferably configured to evaluatethe error rates of presently received data packets as well as of aplurality of previously received data packets, and to estimate orpredict the quality of the future data connection with respect to themaximum latency that is assigned to the respective application module.The communication module is preferably configured to generate thecontrol signal based on a quality value that describes the estimatedquality of the future data connection.

According to a further preferred embodiment, the at least oneapplication module is configured to send a stop request to thecommunication module in response to receiving said control signal,wherein said stop request indicates to the communication modulethat—with respect to said at least one application module—no subsequentdata signal must be exchanged with any other communication module of thecommunication system.

The at least one application module may be configured to carry out thefollowing steps in connection with, or upon, the generation of the stoprequest: starting a timer and sending a re-start request to thecommunication module in response to the expiration of the timer.

The communication module is preferably configured to re-establish thedata transmission with at least one other communication node of thecommunication system with respect to said at least one applicationmodule upon reception of the re-start request. The re-establishing ofthe data transmission preferably includes: sending data signals based ondata received from the application module to at least one othercommunication node of the communication system, receiving data signalsfrom at least one other communication node of the communication system,and transferring the received data signals or the contents of these datasignals to the application module.

According to another preferred embodiment, the at least one applicationmodule may be configured to send a parameter request to thecommunication module in response to receiving the control signal,wherein said parameter request indicates to the communication modulethat the communication module is instructed to proceed with exchangingdata signals with other communication nodes based on a modifiedparameter set that includes a modified quality threshold and/or amodified maximum latency value.

The communication module may be configured to carry out the followingsteps upon reception of the parameter request: evaluating the receiveddata signals and generating an updated quality value that describes thecurrent and/or future quality of the data connection with at least oneother communication node based on the requested parameters of saidreceived parameter set, sending a new control signal to the applicationmodule if said updated quality value is below said modified qualitythreshold of the modified parameter set, and sending a confirmation tothe application module if said updated quality value exceeds themodified quality threshold of said modified parameter set.

As mentioned above, the communication node preferably comprises at leasttwo application modules, to each of which an individual qualitythreshold and an individual maximum latency is assigned. In this case,the communication module is preferably configured to send a controlsignal to each of the application modules for which the assigned qualitythreshold exceeds the quality value for the respective maximum latency.

Furthermore, the communication module may be configured to send itsquality values and latency values that indicate the respective maximumlatencies, to at least one other communication node of the communicationsystem and to evaluate quality and latency values that are received fromat least one other communication node of the communication system.Further, the communication module may be configured to determine itsquality values in combination with the corresponding maximum latenciesbased on, or at least also based on, quality values and latencies thatare received from one or more of the other communication nodes of thecommunication system.

The communication module may be also configured to measure theelectromagnetic radiation on the currently used communication channel,preferably in time slots where no data signals are transmitted betweencommunication nodes of the communication system, and to determine aninterference value that indicates the amount of electromagneticradiation.

The communication module may be further configured to determine thequality value with respect to the corresponding maximum latency basedon, or at least also based on, the interference value.

According to another embodiment, the communication module may beconfigured to measure predefined characteristics of the electromagneticradiation on the currently used communication channel, preferably intime slots where no data signals are transmitted between communicationnodes of the communication system, and to derive an interference valuefrom said measured characteristics of said electromagnetic radiation.

The communication module may be further configured to determine thequality values with respect to the corresponding maximum latencies basedon, or at least also based on, the interference value.

Furthermore, the communication module may be configured to send itsinterference value to at least one other communication node of thecommunication system, and to evaluate interference values that arereceived from at least one other communication node of the communicationsystem.

The communication module may be further configured to determine itsquality value or values with respect to the defined maximum latency orlatencies based on, or at least also based on, interference values thatare received from one or more of the other communication nodes of thecommunication system.

According to a further preferred embodiment, the communication node maycomprise a processor and a memory. The memory preferably stores acontrol software module which—after activation—programs the processor tofunction as a communication module as defined above, and at least oneapplication software module which—after activation—programs theprocessor to function as an application module as defined above.

The control software module is preferably assigned to the physical layeror the data link layer according to the Open Systems Interconnectionmodel, OSI-model.

The at least one application software module is preferably assigned tothe application layer according to the OSI-model.

A further embodiment of the invention relates to a communication systemthat comprises at least two communication nodes as described above.

A further embodiment of the invention relates to a method of operating acommunication node in a communication system. A communication module ofthe communication node transfers data signals received from anothercommunication node of the communication system, or the contents of thesedata signals to an application module of the communication node, andsends data signals based on data received from the application module tosaid other communication node or to at least one other communicationnode of the communication system. The communication module evaluates thereceived data signals and generates a quality value that describes thecurrent and/or future quality of the data connection with respect to agiven maximum latency. The communication module sends a control signalto the application module if the quality value for the given maximumlatency is below a given threshold that is assigned to the applicationmodule.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the manner in which the above-recited and other advantagesof the invention are obtained will be readily understood, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are therefore notto be considered to be limiting of its scope, the invention will bedescribed and explained with additional specificity and detail by theuse of the accompanying drawings in which

FIGS. 1-4 show exemplary embodiments of a token-ring communicationsystem that comprises broadcast-type communication nodes, and

FIG. 5 shows an exemplary embodiment of a communication node in furtherdetail.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention will be bestunderstood by reference to the drawings. It will be readily understoodthat the present invention, as generally described and illustrated inthe figures herein, could vary in a wide range. Thus, the following moredetailed description of the exemplary embodiments of the presentinvention, as represented in the figures, is not intended to limit thescope of the invention, as claimed, but is merely representative ofpresently preferred embodiments of the invention.

FIG. 1 shows a first exemplary embodiment of a communication system 5that comprises a plurality of broadcast-type communication nodes. Thecommunication nodes are designated by reference numerals 10 and 11 inFIG. 1. The communication nodes 10 and 11 may be identical.

The communication module 10 comprises a first application module 21, asecond application module 22, and a communication module 30. Thecommunication module 30 is in charge of managing the data communicationwith the corresponding application modules of the other communicationnodes 11.

To this end, the communication module 30 receives data signals D2 fromthe communication nodes 11 of the communication system 5 and transfersthe contents of these data signals to the respective applicationmodules, i.e. to the application modules 21 and 22 to which the contentof the received data signals is addressed.

In order to enable a data flow in the opposite direction, thecommunication module 30 receives data from the application modules 21and 22 and generates data signals D1 which are then sent to the othercommunication nodes 11 of the communication system 5.

The communication system 5 preferably forms a token-ring system whereineach communication node directly or indirectly—i.e. via one or moreother communication nodes that function as relay nodes—sends datasignals to an allocated downstream communication node and receives datasignals from an allocated upstream communication node. The communicationnodes 10 and 11 are preferably broadcast-type communication nodes.

The communication module 30 of the communication node 10 as well as thecommunication modules of the other communication nodes 11 are furtherconfigured to monitor the quality of the data connection and to generatequality values Q1(T1) and Q2(T2) that indicate the quality of thecurrent communication or the estimated quality of the futurecommunication.

The quality values Q1(T1) and Q2(T2) that are determined by thecommunication module 30 consider tolerable latencies (or tolerable timedelays), preferably application-individually with respect to thecommunication of each application module, i.e. the first applicationmodule 21 and the second application module 22. The maximum latenciesdefine maximum time delays or transmission durations and as suchimplicitly required arrival times for the transmission and reception ofdata, preferably each data packet, at the allocated remote communicationnode(s) 11.

The application-individual latency values that application-individuallyindicate the respective maximum latencies, are designated in FIG. 1 byreference signs T1 and T2, respectively.

The quality values Q1(T1) and Q2(T2) may be determined as follows:

-   Q1(T1)=1 if all data provided by application module 21 can be    transmitted in compliance with the time restraints, or within the    requested time interval, defined by latency value T1 and-   Q1(T1)=0 if all data provided by application module 21 cannot be    transmitted in compliance with the time restraints, or within the    requested time interval, defined by latency value T1, because the    communication is disturbed or interrupted.-   Q2(T2)=1 if all data provided by application module 22 can be    transmitted in compliance with the time restraints, or within the    requested time interval, defined by latency value T2 and-   Q2(T2)=0 if all data provided by application module 22 cannot be    transmitted in compliance with the time restraints, or within the    requested time interval, defined by latency value T2, because the    communication is disturbed or interrupted.

A quality threshold Q1min and Q2min is individually assigned to each ofthe application modules 20 and 21, respectively. The quality thresholdsQ1min and Q2min may differ.

In case of binary quality values as described above, the qualitythresholds Q1min and Q2min may be equal, for instance:

Q1min=Q2min=0.5

Instead of binary quality values, numerical values can be calculatedthat estimate or predict the likelihood of a successful datatransmission within the given maximum latencies. For instance,percentages can be calculated where a value of 0% predicts no chance oflatency-compliant transmission and a value of 100% predicts certainty oflatency-compliant transmission.

To this end, the communication module 30 may evaluate the transmissionrates, bit error rates and/or durations of interruptions in the past inorder to predict the future communication quality and calculate therespective numerical quality values.

For instance, the values Q1 and Q2 may be calculated as follows:

${Q(T)} = \left\{ {\begin{matrix}{1,} & {\ {{{{if}\ \frac{packetsize}{B{\log_{2}\left( {S/N} \right)}}} + t_{start}} < T}} \\{{0,}\ } & {{{{if}\ \frac{packetsize}{B{\log_{2}\left( {S/N} \right)}}} + t_{start}} \geq T}\end{matrix},} \right.$

where B is the system bandwidth, S is the received signal strength ofdata signal D, N is the noise and tstart is the time period from thepacket generation to the start of the packet transmission.

An according future communication quality value Q′ at time T might bedetermined by calculating a weighted average over the last n availablechannel quality values, for example, if n=4, as follows:

Q′(T)=0.4*Q(T)+0.3*Q(T−1)+0.2*Q(T−2)+0.1*Q(T−3).

In the embodiment shown in FIG. 1, it is assumed that the qualitythresholds Q1min and Q2min as well as the latency values T1 and T2 aretransferred from the application modules 21 and 22 to the communicationmodule 30. As such, the application modules 21 and 22 are capable ofmodifying their quality demands if necessary, by sending new or updatedlatency values and/or quality thresholds (for instance in cases ofnon-binary quality values).

During the ongoing communication with the other communication nodes 11,the communication module 30 analyzes the data traffic and generates thequality values Q1(T1) and Q2(T2) as discussed above with respect to eachof the application modules 21 and 22 and the respective maximumlatencies T1 and T2. As such, the communication module 30 takes intoaccount that the transmission of data signals from the applicationmodules 21 and 22 to the other communication nodes 11 may not or shouldnot exceed the tolerable latency for the respective application module21 and 22.

The communication module 30 then compares the application-individualquality values Q1(T1) and Q2(T2) with the application-individual qualitythresholds Q1min and Q2min that are provided by the application modules21 and 22. If any of the quality values Q1(T1) or Q2(T2) is below theapplication-individual quality threshold Q1min and Q2min, thecommunication module 30 sends a control signal QS to the respectiveapplication module 21 or 22.

In the illustrated example, it is assumed that the quality value Q2(T2)exceeds the required minimum quality threshold Q2min. Therefore, thecommunication module 30 can proceed with the communication with respectto the second application module 22.

In the illustrated example, it is further assumed that the quality valueQ1(T1) fails to reach its quality threshold Q1min. In this case, thecommunication module 30 is unable to send data signals on behalf of thefirst application module 21, at least not in compliance with the timerestraints imposed by the maximum latency value T1.

Therefore, the communication module 30 generates a control signal QS andtransmits the control signal QS to the first application module 21. Uponreceipt of the control signal QS, the first application module 21 isaware that the communication with the other communication nodes 11, inparticular with the first application modules of the other communicationnodes 11, is disturbed or compromised and that its data signals cannotbe sent as planned.

In the illustrated example, the first application module 21 comprises atimer 75. After receiving the control signal QS, the first applicationmodule 21 sends a stop request ST to the communication module 30. Thestop request ST indicates that the communication module 30 is instructedto stop data traffic with respect to the first application module 21.

Further, the first application module 21 starts its timer 75 for a givenperiod. When the timer 75 expires, the first application module 21 sendsa re-start request RR to the communication module 30. Upon receipt ofthe re-start request RR, the communication module 30 re-establishes thedata transmission with the other communication nodes 11 with respect tothe first application module 21.

The step of re-establishing the data transmission preferably includes:sending data signals based on data received from the first applicationmodule 21 to the other communication nodes 11; and receiving datasignals from the other communication nodes 11 and transferring thereceived data signals or the contents of these data signals to the firstapplication module 21.

During the resumption of the data connection or thereafter, thecommunication module 30 also resumes monitoring the quality of the dataconnection with respect to the first application module 21: If thequality value Q1(T1) still fails to reach its quality threshold Q1min, anew control signal QS' may be generated and the communication may bepaused again as discussed above. If the quality value Q1(T1) reaches orexceeds the quality threshold Q1min, a confirmation signal OK may besent to the first application module 21 in order to confirm that datacan be sent and received in compliance with the requested maximumlatency T1.

The second application module 22 may react to an incoming control signalQS in the same way as discussed above with reference to the firstapplication module 21, or differently. Hereinafter, with reference toFIG. 2, it is assumed that the second application module 22 takes othermeasures to cope with quality issues.

FIG. 2 shows the communication node 10 of FIG. 1 in case that thecommunication module 30 detects an insufficient quality of the dataconnection with respect to the second application module 22 andgenerates the respective control signal QS.

Upon receipt of the control signal QS, the second application module 22sends a parameter request to the communication module 30. The parameterrequests indicates to the communication module 30 that the communicationmodule 30 is instructed to proceed with exchanging data signals withother communication modules 11, however, based on a modified parameterset that includes a modified, preferably reduced, quality thresholdQ2min′ and a modified, preferably extended, maximum latency value T2′.

After receiving the new parameter set, the communication module 30evaluates the received data signals and generates an updated qualityvalue that describes the current quality of the data connection in viewof the requested new latency value T2′. Depending on the outcome of thisanalysis, the communication module 30 either sends a new control signalQS' (if the updated quality value is still below the modified qualitythreshold Q2min′) or a confirmation signal OK (if the updated qualityvalue exceeds the modified quality threshold Q2min′) to the secondapplication module 22.

FIG. 3 shows an exemplary embodiment of a communication system 5 wherethe communication nodes 10 and 11 exchange their quality values Q1 andQ2 and latency values T1 and T2 in order to enable a calculation ofquality values based on, or at least also based on, quality values andlatencies that are received from other communication nodes of thecommunication system 5.

In the illustrated example, the communication module 30 receives datasignals D2(Q1,T1,Q2,T2) that comprise the quality values Q1 and Q2 andthe latency values T1 and T2 presently assigned to the respectiveapplication modules of at least one of the other communication nodes 11or preferably of all of the other communication nodes 11.

In a corresponding manner, the communication module 30 of thecommunication node 10 generates and transmits data signalsD1(Q1,T1,Q2,T2) that indicate the quality values Q1 and Q2 and thelatency values T1 and T2 that are presently assigned to the applicationmodules 21 and 22 of the communication node 10. Further, thecommunication module 30 may forward the quality values Q1 and Q2 and thelatency values T1 and T2 that were previously received from the othercommunication nodes 11 in order to transmit complete sets of quality andlatency values that refer to each of the communication nodes of thecommunication system 5.

Furthermore, the communication module 30 of the communication node 10may measure the radiation or predefined characteristics of theelectromagnetic radiation on the currently used communication channel,preferably in time slots where no data signals are transmitted betweenthe communication nodes 10 and 11, and determine an interference value Ithat indicates the amount of electromagnetic radiation.

For instance, the communication module 30 may measure the interferencevalue I by using the following formula:

I=∫ _(fmin) ^(fmax) P(f)df

wherein fmax(C) the upper end of the frequency band of the respectivecommunication channel, fmin(C) the lower end of the frequency band ofthe respective communication channel, and P(f) the radiation density.

In case of a time domain multiplexing system, the interference value Ican be obtained by using the following formula:

I=∫ _(tmin) ^(tmax) P(t)dt

wherein tmax the end of the time slot assignment of the respectivecommunication channel, tmin the beginning of the time slot assignment ofthe respective communication channel, and P(t) the radiation density.

If an interference value I is calculated or measured, the communicationmodule 30 may also determine the quality values Q1 and Q2—with respectto the corresponding maximum latency—based on, or at least also basedon, the interference value I. For instance, the values Q1 and Q2 may becalculated as follows:

${Q(T)} = \left\{ {\begin{matrix}{1,} & {\ {{{{if}\ \frac{packetsize}{B{\log_{2}\left( {S/\left\lbrack {N + I} \right\rbrack} \right)}}} + t_{start}} < T}} \\{{0,}\ } & {{{{if}\ \frac{packetsize}{B{\log_{2}\left( {S/\left\lbrack {N + I} \right\rbrack} \right)}}} + t_{start}} \geq T}\end{matrix},} \right.$

where B is the system bandwidth, S is the received signal strength ofdata signal D, N is the noise and tstart is the time period from thepacket generation to the start of the packet transmission.

FIG. 4 shows an exemplary embodiment of a communication system 5 wherethe communication nodes 10 and 11 exchange their quality values Q1 andQ2, their latency values T1 and T2 and their interference values I inorder to enable a calculation of quality values based on, or at leastalso based on, quality values, latencies values and interference valuesthat were received from other communication nodes of the communicationsystem 5.

In the illustrated example, the communication module 30 receives datasignals D2(Q1,T1,Q2,T2,I) that comprise quality values Q1 and Q2 andlatency values T1 and T2 presently assigned to the respectiveapplication modules of at least one of the other communication nodes 11or preferably of all of the other communication nodes 11. The datasignals D2(Q1,T1,Q2,T2,I) further comprise interference values I thatwere previously determined by at least one of the other communicationnodes 11 or preferably by all of the other communication nodes 11.

In a corresponding manner, the communication module 30 of thecommunication node 10 generates and transmits data signalsD1(Q1,T1,Q2,T2,I) that indicate the quality values Q1 and Q2 and thelatency values T1 and T2 that are presently assigned to the applicationmodules 21 and 22 of the communication node 10 as well as theinterference value I determined by the communication module 30. Further,the communication module 30 may also forward the quality values Q1 andQ2, the latency values T1 and T2 as well as the interference values thatwere previously received from the other communication nodes 11 in orderto transmit complete sets of quality and latency values as well asinterference values that refer to each of the other communication nodesof the communication system 5.

FIG. 5 shows an exemplary embodiment of a communication node 100 thatcan form any of the communication nodes 10 and 11 in FIGS. 1-4. Thecommunication node 100 comprises a processor 110, a memory 120, and atransceiver 200.

The memory 120 stores a control software module 130 which—afteractivation—programs the processor 110 to function as a communicationmodule 30 as described above in connection with the communication node10 in FIGS. 1-4.

The memory 120 further stores two application software modules 121 and122 which—after activation—program the processor 110 to function asapplication modules 21 and 22, respectively, as described above inconnection with the embodiments shown in FIGS. 1-4.

The control software module 130 is preferably assigned to the physicallayer or the data link layer according to the Open SystemsInterconnection model, OSI-model.

The application software modules 121 and 122 are preferably assigned tothe application layer according to the OSI-model.

1. Communication node (10, 11) for a communication system (5),characterized by: a communication module (30), and at least oneapplication module (21, 22), wherein the communication module isconfigured to transfer data signals (D2) received from anothercommunication node of the communication system, or the contents of thesedata signals, to the application module, and to send data signals (D1)based on data received from the application module to said othercommunication node or to at least one other communication node of thecommunication system, wherein the communication module is configured toevaluate the received data signals and to generate a quality value(Q1(T1), Q2(T2)) that describes the current and/or future quality of thedata connection with respect to a previously defined maximum latency(T1, T2) that is assigned to the application module, and wherein thecommunication module is further configured to send a control signal (QS)to the application module if the quality value is below a given qualitythreshold (Q1min, Q2min) regarding the respective maximum latency thatis assigned to the application module.
 2. Communication node of claim 1,characterized in that said data signals are encoded data packets, andthe communication module is configured to decode the received datapackets and to determine the quality value based on, or at least alsobased on, the error rate of said received and decoded data packets. 3.Communication node of claim 1, characterized in that the communicationmodule is configured to evaluate the error rates of presently receiveddata packets as well as of a plurality of previously received datapackets, and to estimate or predict the quality of the future dataconnection with respect to the maximum latency assigned to theapplication module, and the communication module is further configuredto generate said control signal based on a quality value that describesthe estimated quality of the future data connection.
 4. Communicationnode of claim 1, characterized in that said at least one applicationmodule is configured to send a stop request (ST) to the communicationmodule in response to receiving said control signal, wherein said stoprequest indicates to the communication module that—with respect to saidat least one application module—no subsequent data signal must beexchanged with any other communication module of the communicationsystem.
 5. Communication node of claim 4, characterized in that said atleast one application module is configured to carry out the followingsteps in connection with, or upon, the generation of the stop request:starting a timer (75) and sending a re-start request (RR) to thecommunication module in response to the expiration of said timer, andsaid communication module is configured to re-establish the datatransmission with at least one other communication node of thecommunication system with respect to said at least one applicationmodule upon reception of the re-start request.
 6. Communication node ofclaim 1, characterized in that said at least one application module isconfigured to send a parameter request to the communication module inresponse to receiving said control signal, wherein said parameterrequest indicates to the communication module that the communicationmodule is instructed to proceed with exchanging data signals with othercommunication modules based on a modified parameter set that includes amodified quality threshold (Q2min′) and/or a modified maximum latencyvalue (T2′).
 7. Communication node of claim 6, characterized in that thecommunication module is configured to carry out the following steps uponreception of the parameter request: evaluating the received data signalsand generating an updated quality value that describes the currentand/or future quality of the data connection with respect to therequested parameters of said received parameter set, sending a newcontrol signal to the application module if said updated quality valueis below said modified quality threshold of the modified parameter set,and sending a confirmation to the application module if said updatedquality value exceeds the modified quality threshold of said modifiedparameter set.
 8. Communication node of claim 1, characterized in thatthe communication node comprises at least two application modules, toeach of which an individual quality threshold and an individual maximumlatency is assigned, and the communication module is configured to senda control signal to each of the application modules for which theassigned quality threshold exceeds the quality value for the respectivemaximum latency.
 9. Communication node of claim 1, characterized in thatthe communication module is configured to send its quality values andlatency values that indicates the respective maximum latencies, to atleast one other communication node of the communication system and toevaluate quality and latency values that are received from at least oneother communication node of the communication system, and wherein thecommunication module is further configured to determine its qualityvalues in combination with the corresponding maximum latencies based on,or at least also based on, quality values and latencies that arereceived from one or more of the other communication nodes of thecommunication system.
 10. Communication node of claim 1, characterizedin that the communication module is configured to measure theelectromagnetic radiation on the currently used communication channel,preferably in time slots where no data signals are transmitted betweencommunication nodes of the communication system, and to determine aninterference value (I) that indicates the amount of electromagneticradiation, and the communication module is further configured todetermine the quality value with respect to the corresponding maximumlatency based on, or at least also based on, the interference value. 11.Communication node of claim 1, characterized in that the communicationmodule is configured to measure predefined characteristics of theelectromagnetic radiation on the currently used communication channel,preferably in time slots where no data signals are transmitted betweencommunication nodes of the communication system, and to derive aninterference value from said measured characteristics of saidelectromagnetic radiation, and the communication module is furtherconfigured to determine the quality values with respect to thecorresponding maximum latencies based on, or at least also based on, theinterference value.
 12. Communication node of claim 10, characterized inthat the communication module is configured to send its interferencevalue to at least one other communication node of the communicationsystem, and to evaluate interference values that are received from atleast one other communication node of the communication system, andwherein the communication module is further configured to determine itsquality value or values with respect to the defined maximum latency orlatencies based on, or at least also based on, interference values thatare received from one or more of the other communication nodes of thecommunication system.
 13. Communication node of claim 1, characterizedin that the communication node comprises a processor (110) and a memory(120) that stores a control software module (130) which—afteractivation—programs the processor to function as a communication moduleas defined above, and at least one application software module (121,122) which—after activation—programs the processor to function as anapplication module as defined above, wherein said control softwaremodule is assigned to the physical layer or the data link layeraccording to the Open Systems Interconnection model, OSI-model, andwherein said at least application software module is assigned to theapplication layer according to the OSI-model.
 14. Communication systemcomprising at least two communication nodes, characterized in that atleast one of the communication nodes is a communication node accordingto any of the preceding claims.
 15. Method of operating a communicationnode in a communication system, characterized in that a communicationmodule of the communication node transfers data signals received fromanother communication node of the communication system, or the contentsof these data signals, to an application module of the communicationnode, and sends data signals based on data received from the applicationmodule to said other communication node or to at least one othercommunication node of the communication system, the communication moduleevaluates the received data signals and generates a quality value thatdescribes the current and/or future quality of the data connection withrespect to a given maximum latency, and the communication module sends acontrol signal to the application module if the quality value for thegiven maximum latency is below a given threshold that is assigned to theapplication module.
 16. Communication node of claim 11, characterized inthat the communication module is configured to send its interferencevalue to at least one other communication node of the communicationsystem, and to evaluate interference values that are received from atleast one other communication node of the communication system, andwherein the communication module is further configured to determine itsquality value or values with respect to the defined maximum latency orlatencies based on, or at least also based on, interference values thatare received from one or more of the other communication nodes of thecommunication system.